The low voltage transmission EM revolutionized our understanding of cell and tissue structure and the intermediate voltage microscope represents a significant development in transmission EM which is now available for wide use. Intermediate voltage electron microscopy permits study of thick (250 to 1000 nm) and thin (60 to 100 nm) tissue sections, whole cell mounts, macromolecular aggregates and isolated macromolecules. Equipped with a goniometer stage this microscope will permit stereoscopic analyses of molecules, molecular aggregates and cell and tissue structures. The STEM will permit study of unstained specimens and provide new ultrastructural information to correlate with ongoing ultrastructural and x-ray diffraction studies which heretofore have not been possible. At Rutgers Medical School there are highly qualified investigators of matrix structure and biology in the Departments of Pathology, Biochemistry and Medicine studying: tissue ultrastructural of morphogenesis and repair reactions; cell biological and biochemical studies of matrix production and degradation; collagen gene structure and function; X-ray diffraction of tissues and reconstituted macromolecular aggregates; laser light scattering of isolated matrix molecules; ultrastructural studies of isolated matrix molecules and their aggregate forms; biomechanical properties of normal and reconstituted matrices; clinical, biochemical, genetics and pathological studies of inherited and acquired diseases of the connective tissues. We request funds for the purchase of an intermediate voltage, high resolution microscope from JEOL, the 2000-EX, with STEM capacity. This instrument will enable Rutgers Medical School and particularly the investigators and supporting collaborators included in this application to continue current studies and expand into new areas of connective tissue research.